Yagi antenna having matching coaxial cable and driven element impedances
First Claim
1. A Yagi antenna, comprising:
- an insulative circuit board having a proximal end and a distal end;
a J-shaped driven element having an impedance Ω
d and being printed on a top surface of the circuit board, wherein the J-shaped driven element comprises a short portion, a long portion that is twice as long as the short portion, and a connecting portion connecting the short portion and the long portion, the short and long portions being parallel to each other, and wherein a mid-point of the long portion of the J-shaped driven element is grounded;
one or more director elements printed on a top surface of the circuit board at a position located between the distal end of the circuit board and the J-shaped driven element;
a reflector element printed on a bottom surface of the circuit board at a position located between the proximal end of the circuit board and the J-shaped driven element;
a microstrip transmission line printed on the circuit board, the microstrip transmission line having a proximal end, a distal end, and an impedance Ω
w, the distal end of the microstrip transmission line being electrically connected to the J-shaped driven element; and
a cable having an impedance Ω
c, the cable being electrically connected to the proximal end of the microstrip transmission line, wherein the impedance Ω
c matches the impedances Ω
d and Ω
w.
1 Assignment
0 Petitions
Accused Products
Abstract
A printed Yagi antenna of the present invention has a circuit board, a driven element having an impedance Ωd and being printed on the circuit board, a director element printed on the circuit board, a reflector element printed on the circuit board, a microstrip transmission line, and a coaxial cable having and impedance Ωc. The coaxial cable feeds the driven element via the miscrostrip transmission line and Ωc is approximately equal to Ωd. Further, the spacing between the reflector element, the driven element, and director elements are chosen so that an optimum balance is achieved between directional gain and performance sensitivity. The printed Yagi antenna has a partial folded driven element having a J shape which is grounded at the mid-point of the longest portion of the element. The configuration allows for a coaxial cable to be attached directly to the microstrip transmission line without the use of a matching network or balun.
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Citations
21 Claims
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1. A Yagi antenna, comprising:
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an insulative circuit board having a proximal end and a distal end;
a J-shaped driven element having an impedance Ω
d and being printed on a top surface of the circuit board, wherein the J-shaped driven element comprises a short portion, a long portion that is twice as long as the short portion, and a connecting portion connecting the short portion and the long portion, the short and long portions being parallel to each other, and wherein a mid-point of the long portion of the J-shaped driven element is grounded;
one or more director elements printed on a top surface of the circuit board at a position located between the distal end of the circuit board and the J-shaped driven element;
a reflector element printed on a bottom surface of the circuit board at a position located between the proximal end of the circuit board and the J-shaped driven element;
a microstrip transmission line printed on the circuit board, the microstrip transmission line having a proximal end, a distal end, and an impedance Ω
w, the distal end of the microstrip transmission line being electrically connected to the J-shaped driven element; and
a cable having an impedance Ω
c, the cable being electrically connected to the proximal end of the microstrip transmission line, wherein the impedance Ω
c matches the impedances Ω
d and Ω
w.- View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A radio receiver system, comprising:
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a radio receiver having an input and an output;
an insulative circuit board having a proximal end and a distal end;
a J-shaped driven element having an impedance Ω
d and being printed on a top surface of the circuit board, wherein the J-shaped driven element comprises a short portion, a long portion that is twice as long as the short portion, and a connecting portion connecting the short portion and the long portion, the short and long portions being parallel to each other, and wherein a mid-point of the long portion of the J-shaped driven element is grounded;
one or more director elements printed on the top surface of the circuit board at a position located between the distal end of the circuit board and the J-shaped driven element;
a reflector element printed on the circuit board at a position located between the proximal end of the circuit board and the driven element;
a microstrip transmission line printed on the circuit board, the microstrip transmission line having a proximal end, a distal end, and an impedance Ω
w, the distal end of the microstrip transmission line being electrically connected to the J-shaped driven element; and
a cable having a first end, a second end, and an impedance Ω
c, wherein the first end is electrically connected to the proximal end of the microstrip transmission line, and the second end is electrically connected to the input of the receiver, and wherein the impedance Ω
c matches the impedances Ω
d and Ω
w.- View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A transmitter system, comprising:
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a transmitter having an input and an output;
an insulative circuit board having a proximal end and a distal end;
a J-shaped driven element having an impedance Ω
d and being printed on a top surface of the circuit board, wherein the J-shaped driven element comprises a short portion, a long portion that is twice as long as the short portion, and a connecting portion connecting the short portion and the long portion, the short and long portions being parallel to each other, and wherein a mid-point of the long portion of the J-shaped driven element is grounded;
one or more director elements printed on the top surface of the circuit board at a position located between the distal end of the circuit board and the driven element;
a reflector element printed on a bottom surface of the circuit board at a position located between the proximal end of the circuit board and the J-shaped driven element;
a microstrip transmission line printed on the circuit board, the microstrip transmission line having a proximal end, a distal end, and an impedance Ω
w, the distal end of the microstrip transmission line being electrically connected to the J-shaped driven element; and
a cable having a first end, a second end, and an impedance Ω
c, wherein the first end is electrically connected to the proximal end of the microstrip transmission line, and the second end is electrically connected to the output of the transmitter, and wherein the impedance Ω
c matches the impedances Ω
d and Ω
w.- View Dependent Claims (16, 17, 18, 19, 20, 21)
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Specification